Many different embodiments of so-called sports boards designed for use in sports activities and other leisure-time use are known. There are, for example, boards for use on snow or ice surfaces in the form of toboggans, sledges and devices equipped with skids.
Furthermore, different board types are known, generally of an inflatable nature, designed to be pulled behind a boat on water, where the user is quite simply towed behind the boat or has the possibility of riding some form of slalom.
Moreover, there are also board structures, also of the air cushion type, which can be used to sledge down, e.g., a grassy slope.
However, to date there have been no devices for active sports and leisure time use which are so designed that they are equally suitable for use on different types of surfaces, as for instance snow and water.
A snow covering and a water surface have very different properties, which will affect the propulsion of a vehicle moving on these surfaces. A sliding surface that is designed for turning on snow or a compressed snow cover will not work in the same way in an aquatic environment, where, for example, a steering rib will not be able to grip the surface, but instead will function by pushing water aside.
Examples of special boards for sledging can be found in Norwegian Patent No. 165098, which describes a board with a padded support for the user and with a groove on its underside to render the sledge steerable on snow surfaces. A design according to this patent would not be usable on water.
Examples of structures designed for use both on water and on snow are described in U.S. Pat. No. 4,732,399, DE Offenlegungsschrift 2528842 and WO-A1-87/04397. The device in U.S. Pat. No. 4,732,399 is made of an inflatable cushion, preferably in the form of an annular ring, with a covering member that surrounds and encloses the cushion. The device is not equipped with any steering grooves or the like and is purely intended for sledging down a slope or being towed behind a boat, and the object of the invention is quite simply that the user should sit comfortably on the air cushion, which naturally also forms the float at sea.
DE 2528842-A-1 teaches a sports device that is made of a rigid plate-shaped part and a flexible, inflatable part or cushion. The structure is primarily intended for use on snow surfaces and is made having a hard, plate-shaped top and an inflatable bottom, which also forms the sliding surface. This may be equipped with steering grooves, and to reduce wear may also be covered with a bottom shell or turned upside-down so that the hard part forms the sliding surface. A number of different embodiments based on this principle are described. When sledging on this board, the user sits on the air cushion with his legs facing forwards in a normal sitting position and can balance the board by leaning to the sides, thereby obtaining some control. For use on a water surface, the device according to the German document is modified. Paddles, for example, are mounted, and the user sitting on the board can propel himself forwards by turning the paddles that are arranged on a shaft which is passed through the board. The board is thus essentially suitable for leisure purposes at sea and must be modified to be capable of being used in the water.
WO-A1-87/04397 describes a device for use preferably in activity on a snow-covered surface, but which may also be used on water. The device has a bottom board with a slightly curved central portion, higher side portions and central steering grooves or ribs that extend over the whole length. The device further consists of a top board. The bottom board and the top board are joined together along their edges. Fastening means for a towing line, e.g., the hook on a ski lift, are also described. The user sits inside the device and steers by shifting his body weight. The top board may be shaped like a canoe. For alternative use in water, the canoe-shaped top board is secured to the bottom board in such manner that the canoe part can be removed. The device described in this document is not a universal board but a device that must be modified for use in water.